This January 2003 Final Environmental Impact Statement evaluates proposed highway improvements in southwest King County, Washington, including an extension of SR 509 and upgrades to I-5 between South 210th Street and South 310th Street to improve regional access to Seattle-Tacoma International Airport. Three build alternatives and a No Action Alternative are assessed, with the SR 509 extension designed to accommodate two general purpose lanes and a center high-occupancy vehicle lane in each direction. The project was jointly prepared by the Federal Highway Administration, Washington State Department of Transportation, Port of Seattle, King County, and the Cities of SeaTac and Des Moines.Open full document
Notes
This Final Environmental Impact Statement (FEIS) and Section 4(f) Evaluation covers proposed improvements to SR 509 and I-5 in southwest King County, Washington, including an extension of SR 509 to enhance southern access to Seattle-Tacoma International Airport. Three build alternatives and a No Action Alternative are evaluated, differing in their proximity to Des Moines Creek Park, the airport Runway Protection Zone, and their connection to I-5. The document was prepared jointly by FHWA, WSDOT, Port of Seattle, King County, City of SeaTac, and City of Des Moines.